Power transmission



Dec. 5, 1967 B. F, BOEHM 3,355,966

POWER TRANSMISS ION Filed Aug. lO, 1964 United States Patent Oftice n3,355,966 Patented Dec. 5, 1967 3,355,966 POWER TRANSMISSION Benjamin F. Boehm, Oak Park, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 10, 1964, Ser. No. 388,395 3 Claims. (Cl. '74-688) This invention relates in general to power transmissions and more particularly to automatic transmissions incorporating a hydrodynamic torque converter and a multiratio gear unit to provide torque converter drives, split torque drives and direct mechanical drives.

In the modern internal combustion engine vehicle, it is necessary to multiply the torque of the engine to initially move the vehicle through its drive wheels. However, as the vehicle gains momentum, the requirement for torque multiplication varies and diminishes until a vehicle speed is reached where no torque multiplication is needed and overdrive is desirable. To provide for such varying torque requirements in modern vehicles, a power transmission incorporating a hydrodynamic torque converter coupled with multiratio gear unit is often employed. Such transmissions are connected between the vehicle engine, providing a power input, and the drive wheels of the vehicle. The dependability, efliciency, and success of these power tranmissions is witnessed by their widespread application in many varied types of vehicles.

To further increase the drive etliciency, it is desirable to provide an overdrive to obtain an increase in speed from the engine to the drive wheels when there is no need for full engine torque. Such overdrives reduce engine wear since the power transmission output will be rotating faster than the engine crankshaft and still produce the desired vehicle speed. Since the vehicle engine speed is slower, greater fuel mileage is obtained and engine vibrations are diminished resulting in greater passenger comfort.

Generally, these overdrives have heretofore been in the form of special planetary gear units attached directly to the output of the multiratio gear unit of the automatic transmission. These overdrive units have therefore added to the complexity and cost of the vehicle as well as maintenance costs'.

f Thisinvention employs a torque converter unit with a bladed pump adapted to impel a vortex of hydraulic fluid against the blades of a turbine to drive the turbine and a stator located between the pump and turbine to redirect the vortex of hydraulic iiuid from the turbine back into the pump at increased velocity. The torque converter is combined with a multiratio gear unit to provide for varying torques required in the eieient operation of the vehicle. In its preferred embodiment the multiratio gear unit has a compound planetary gear set having large and small sun gears, short planet gears which mesh with the small sun gear, long planet gears which mesh with the large sun gear andfshort planet gears, a large reverse ring gear meshing with the short planets and a smaller overdrive ring gear meshing with the long planet gears. A suitable carrier rotatablymounts the long and short planet gears in the planetary gear set and provides the output of the planetary gear set. Suitable braking structures, such as bands, are provided for the small sun gear to selectively hold this gear to provide proper gear ratio in the forward speeds when increased torque multiplication is desired, while a similar braking structure is provided for the large ring gear for reverse. I

In a first embodiment for low, the turbine is connected directly to and drives the large sun gear of the planetary gear set through a suitable drive connection While the small sun gear is held to provide for carrier output with large gear reduction needed to initially move the vehicle.

For converter drive combined with direct drive in the gearing, the small sun gear is released from reaction and a clutch device is engaged to connect that sun gear with the turbine drive connection connecting the turbine and the large sun gear. This causes both sun gears to simultaneously rotate in the same direction locking the gear set as a unit and rotating the output carrier to the sun gears. An optional direct mechanical drive is obtained by clutching the sun gears for rotation together locking up the planetary gear set. The gear set is then driven as a unit by the input ring gear when connected directly to the input shaft by a suitable clutch. Reverse is obtained by braking the ring gear for the short planets and driving the large sun gear with the turbine. The short planets, actuated by the input gear, will walk around in the reaction ring gear in a reverse direction taking the output carrier in that direction. An overdrive in this embodiment is obtained without the addition of a special overdrive unit by braking the small sun gear and driving the long planet ring gear directly from the engine input through the second clutch as in direct drive with split torque. However, in overdrive the torque converter is evacuated by a special valve device to prevent it from retarding the movement of the carrier due to the fact that pump speed is greater than turbine speed. Overdrive is obtained as the short planet races around the reaction sun gear in a forward direction at a speed greater than the speed of the input ring gear.

A second embodiment is similar to the first embodiment described above. However, the clutch for the small sun gear of the planetary unit has been eliminated and a one- Way clutch has been installed in the drive connection between the turbine and the large input sun gear. Additionally, a manually operable clutch has been installed in parallel with the one-way clutch to provide a positive connection between the torque converter and the planetary gear set. This manual clutch permits the vehicle to be started by pushing and is also useful in braking the vehicle with the engine. In manual low the manually operated clutch is applied and the small sun gear is held for reaction. Torque multiplication occurs as the short planets.

walk around the reaction sun gear in a clockwise direction when driven by the input sun gear and the intermediate long planets. In automatic loW, the above-mentioned mechanical clutch is released and the small sun gear is held by a braking device. Torque converter input is applied to the large sun gear through the one-way clutch and torque multiplication occurs as the short planets walk around the reaction sun gear moving the carrier. In this second embodiment it is also possible to obtain a split torque drive with a substantially 1 to 1 drive ratio between input and output by clutching the input from the engine directly to the input ring gear while at the same time driving `the large input sun gear by the-turbine, through the one-way clutch. Carrier output is obtained as the long planets rotate slowly and are carried around the input sun gear. In overdrive, obtained as described above in connection with the tirst embodiment; thefsrnaller sun gear is held for reaction with direct mechanical input through the ring gear engaging the long planets. Overdrive is obtained as the carrier moves with the short planets as they race around the reaction sun gear. In this overdrive, evacuation of the converter is not necessary as in the first embodiment since the freewheel device will. permit the large held for reaction and the short planets are rotated clockwise by the long planets driven by the input sun gear.

Since the short planets walk counterclockwise in the reaction ring gear the carrier will be rotated in that direction. 1

A third embodiment of this invention is similar in struc- 3 ture and operation to the second embodiment described above. However, the direct mechanical drive to the input ring gear of the planetary gear unit has been eliminated and replaced by a drive actuated by the turbine of the torque converter;

An' ob'je'ct o'f'this invention is to provide a power transmission includinga torque converter and. aV cooperating planetary gear set which is adaptedv to provide underdrive's, intermediate drives, overdrive and reverse.

Another obje'ct of. this invention is to provide a transmission' havingV a planetary gear set which includes first and second'. input gear means, output means, means connecting the input' means to the output means, and dual input drives with one ofthe input drives providing a torque path' including atorque converter to the iirst input gear' means, and' the other ofthe input drives providing.

atorque path to the second input gear means to provide mechanical' input' independentv of the torque converter.

Another' object' of this invention is to provide a torque converter'trans'mission having a planetary gear set` which4 includes input gear means, output` means and reaction gear `means which is brake'd to. provide a ratio change, and' an; input' drive' providing a torque path and direct mechanical'l input to theV inputl meansV independent of the torque' converter.

A" further object ofthis invention is'to provide a transmission having" a. planetary gear set which includes input means an'd voutput means' and reaction means with the inputmea'ns' formed by a' ring'` gear adapted to be connected to'anddriven' by a power source to obtain an overdrivegear'ratio.

Another object of this invention is to provide a torque convertertra'nsmission" including a planetary gear set for multiplying `torque with an--input' sunA gear connectedl to the kturbin'efljyf aA drivev connection having a` clutch meansV and a" one-Way'4 clutch' connectediin parallel in the drive connection between; the-turbine andthe input sun gear.

Alfrthereobject ofithi's-invention is to providea torque convertertransmissionr including aY compound planetary gearf-setlhavingy dual input gears, an output, and gear meansl connecting" th'e dual input' gears and dual inputf dri-ves'l providedf by'v a/V first" drive' throughf the torqueV converterftolartirstinput` gear and `a-second drive to provide a' Vmechanical input independent" of the torque converter which'combine to'form asplit'torquedrive.

Anothersobject of= this' invention* is toprovide a torque converter transmission having'v a compound planetary g'e'arsetY with ari-"inputr ring l'gear' adapted to be connected to anddriven'by an` input shaftianda reaction'sun gearhe'ldtofprovidean'overdrive.

Thesef and` otherobjects of this 'invention willA become more apparent fromtheV following'speciication and drawingsashowing lthe preferrediembodinentsofthis invention.

FIGURE 1: is'-a schematic view'illustrating a'transmission'incorporating' a' turbine torque converter and a compoundfplanetary-gear-setrliavingadirect drive input ring gear;

l FlGURlEtZis aschematicv view similar to FIGURE 1 illustrating a second' embodiment of f the present invention, and" FIGUREi 31is-- af schematic view'l of` a torque" converter similarI torthat` of"FIG.= 2 and illustrating av further ernbo'diinent ofthe presentvinvention;

The'y transmission shown, in FIG.. lincludes a torque converterf 11 formedi withd a' conventional bladedpump- 3, a bladed turbineand blad'edf statorv 9. TheI pump is adapted to'b'e-rotatablydriverrby an engine input shaft lflconnectedito'thetorque'converter housing 13.y Stator whichprevents stator#A rotation opposite to the forward direction ofrotation-of pump'3f The groundsleve is bine 5'; is'l connected to-the hubofl the'sunY gear 21 ofl a torque-multiplying planetary gear set 23. The-planetary gear set is formed with three long planets 25,..rotatably. mounted on a carrier, which mesh with the sun gear 21 and a surrounding ring gear 27. These long planets are further in meshing engagement near the ends thereof with three short planets 29 which in turn are rotatably mounted on the carrier and meshingly engage a second sun gear 31 and alsoA a surrounding ring.Y gear Sir-whichforms a part of: the compound planetary gear `set-L The hub of the sun gear 31 is secured to a sleeve 35ofy a rotatable housing 37. AsV illustrated, spaced clutch plates 39 splined on the rotary housing ST'are adapted to be selectively engaged by clutch platesf 41 splined on...the periphery of a disc member 43 which is fixed onf andv ro.'- tatable with the turbinesleeve shaft 19. Theouter periph.- ery of housing 37 isadaptedv to be contacted" by brake band 47 to prevent rotation of the housing and the `sun gear 3i while a-.second brake band. 49 is adaptedto` selectively engage the outer periphery of ring gear 33` to,l prevent rotation of that gear, if. desired. Ring gear. 27 is connected by a drum to adirect' drive shaft 51 whichA in turn is connectedto the input 11 througha: clutch 5,3 which provides direct rotation of thering gear. by the, engine input shaft.V The rotatable carrier shown schematically as element 61 is connected to the long. planets. 25 by collar 63 and to the short planets 29 bysuitab'lepivot shafts, not shown. An output shaft 65 isV fixed-to. the carrier ands is adapted to be rotated therewith on ro.- tation of the carrier by the movement ofthe planets-.in their orbits aroundtheir respective sun gears.V Thetorquetransmitted by the rotating shaft 65 can be applied tol the drive wheels of a vehicle through suitable differential gearing which is Vnot shown.

A valve 67 schematically illustratedin FIG. l is. p rovided in the torque converter housing 13' to control` the exhaust of hydraulic huid in the converter to. a sump' 681 for a purpose which will appear below. This valve and connections to the sump are similar inV construction and? in operation to the valve and connections shown'` andA disclosed in U.S. Patent 2,898,738`iss'ued to D'. R..Sa`ndI et al. As shown, the valve 67 includes apiston69 dividing the vvalve chamber into first and' sec'oiidcompa'rtments 71 and 73'. The'iir'st compartment 71 is-connected. to a huid' pressure source such'ash'ydrauli'c pump' 75b'y fluid conduit 77w'hile conduitv 74 connects the second` compartment' to sump 68; The piston 69'is-adaptedftobeV biased by a suitable coil s'p`ring'79into Contact with the. interior of the housing 13. When so biased, as' illustrated' in FIG. l, the -piston is -movediaway fromY a port"8'1l lead.- inginto the chamber. This'piston` movement'allowsthe" fluid tobe discharged from the converterK through the' valve= chamber' into conduit 74I leading into? thev sump: The-'piston 69is also-adapted-to beacteduponby iiuid' pressure ydevelopeddnypump and :supplied 'to`one' end* of the valve'ch'amber through the conduit 77. Whensufli` cient fluid pressure isappliedlto the' pis'ton'the'force' of springl 79' on piston 69 willr be overcome -and the; pistonV will' be moved inwardly to blockport 81"' to prevent evacuation of iluid' from the torqueconverter.

To v provide the necessary uid for-the-operation'ofthe' torque: converter, conduit 82 is utiliedf tol connectC the gear pump 75-'tothefconverter while return'co'nduit 84 connects theconverter to the'surnpt68=throughconduitz 741 A' valve 83'including-a spool with'lands' 85'-1 :on'1'1e"cter1i in conduits 77"l and827'is' utili'zed'to controlthe owof"y fluid tothe converter'15and`the valve-67.K Thisvalvesin: turn controlled by movement ofac'tuatorf 87.a Asrshown; thelands block passagesin` thevalve83 leading to the pump'- 75' and preventv the hydraulicV iluid pressuretdeveloped by the pump from-freaching the piston"7i1` andthe torque converter. In the valve positions'hown; theA hydraulic Vfluid willbesexpelled from th'e'convertertothe sump'through valve167'and conduit 74.1 When the-:valve: spoolfismoved'to thefleft in FIG; lthe conduits 82 and? 77 areopen-to-uidpressure and piston-69 willbemovedi inwardly blocking port 81r` to prevent eXh'austaot-.uida

to the sump through conduit 74. The turbine is then operative to transmit torque to the multiratio gear unit.

In he arrangement shown in FIG. 2, which is similar in construction to that of FIG. 1, with like parts being identified by like reference numerals, a freewheel device such as a one-way clutch 91 to connect the two portions of turbine sleeve shaft 119 extending between turbine 5 and sun gear 21. Also, a selectively operated clutch 93 has been similarly interposed in the turbine input shaft in parallel with the one-way clutch. As illustrated, one portion of the shaft carries a clutch housing 95 having integral clutch plates 97 splined thereon adapted to engage clutch plates 99 splined to a hub 100 integral Vwith the other portion of the turbine sleeve shaft. To operatively connect the input ring gear to direct mechanical input, a`second clutch 101 is disposed between the ring gear 27 and the direct drive shaft 151.

It will be appreciated that the clutches 53 and 39 of FIG. lconstruction have been eliminated in the construction of FIG. 2 since they are unnecessary in the operation of FIG. 2, as described below. Also, the means of FIG. 1 for evacuating the torque converter have been eliminated from the construction of FIG. 2 since evacuation of the torque converter is not necessary to obtain mechanical overdrive as in the embodiment of FIG. l.

In the modification of FIG. 3, which is similar in construction to FIG. 2, with like parts being identified by like reference numerals, shaft 251 is driven directly by turbine 5 instead of being directly driven by input shaft 11. The planetary gear yunit and the same clutches and brakes of FIG. 2 are combined with the torque converter of FIG. 3 so that the turbine 5 drives the input ring gear 27 through theshaft 251 and when clutch 101 is engaged.

The torque converter in itself is conventional and operates in a conventional manner briefly described below. As shown in FIG. 1, the bladed torque converter pump 3 is attached to the engine input shaft 11 through the torque converter housing 13 and is adapted to be driven by that shaft. The centrifugal force developed by the pump when rotated throws the hydraulic fluid out of openings formed by its blade near its rim into similar openings formed by the blades of the turbine. This fluid travels in a vortex and is returned to the pump by the blades in the stator 9 which isheld from rotation by the one-way brake 17. The returning fluid adds its velocity to the velocity of the fluid developed by the pump. By this regenerative means sufficient velocity is obtained to rotate the turbine and drive shaft 51 for torque multiplication. Increases in pump speedA result in increases in turbine speed. As turbine speed approaches pump speed, torque multiplication decreases and the Huid flow is rotary providing a fluid coupling with a 1:1 input to output ratio.

OPERATIONw-FIGURE 1 In the structure shown in FIG. 1 the brake band 47 is applied for underdrive or low-range operation. On application of band 47 thelsun gear 31 becomes a reaction memberl for the planetary gear set. The turbine 5 when driven by input shaft 11 drives sun gear 21 in a clockwise direction which, in turn, rotates the long planets 25 counterclockwise. The long planets will then rotate the short planets 29 clockwise and the short planets will walk around4 the reaction sun gear 31 in clockwise direction. Thus,'the short planets and the long planets and their carrier 61 rotate around the input sun gear 21 with an increased torque applied to the `output shaft. This underdrive provides torque multiplication in the converter and in the gear unit.

t In direct drive, utilized when the vehicle is moving and the requirement for torque multiplication has diminished, the clutch 41 is applied and the sun gears 31 and 21 are simultaneously driven by the turbine output shaft 19. When these two gears rotate in the same direction, the long Vand short planets lock up and are carried as a unit with their respective ring gears with the sun gears.

With this arrangement, the torque converter provides torque multiplication and the gear unit provides 1:1 drive.

With the transmission of FIG. 1 described above, it is also possible to obtain an optional direct mechanical drive with a 1:1 drive ratio. This is accomplished by engaging clutches 53 and 41. With clutch 53 engaged, ring gear 27 is driven in the forward direction by the drive shaft 51 connected directly to input shaft 11 by the clutch 53. However, since clutch 41 has also been applied the gears of the planetary unit are locked and there is a direct or 1:1 solid mechanical drive from input to output.V

During this drive the torque converter does not transmit torque but may remain lled since the pump and turbine are rotating at the same speed.

When overdrive is desired clutch 53 and brake band 47 are applied. This results in direct mechanical input into the planetary gear drive unit through ring gear 27 with reaction provided by sun gear 31. With the sun gear 31 held and with planets 29 and 25 supported on the common carrier 61, planet 29 rapidly rotates and orbits in a forward direction around the reaction sun gear 31. Planets 25 rotate in an opposite direction Vto planets 29 and at a slower speed orbiting within ring gear 27 and in a forward direction. This rotates the common carrier in a forward direction, the planets 2S under these conditions will race ahead of the slower input ring gear. Since `the ratio of pump speed to turbine speed is about 1.45 to 1 in overdrive, it is necessary to evacuate the torque converter to prevent the input sun gear from retarding the rotation of the planetary gears. The torque converter of FIG. 1 is evacuated in overdrive by movement of the lands to cutoff the supply of fluid to valve 67 and the torque converter. When fluid pressure is removed from piston 69, the valve is opened by movement of the piston and the converter fluid exhausts into the sump 68.

In reverse, brake 49 is applied to the ring gear 33. The turbine drives sun gear 21 in a forward direction which in turn drives planet 25 in an opposite direction. The large planet 29 which meshes with the short planet is driven thereby and rotates in the same direction as sun gear 21 and walks counterclockwise in the reaction ring gear 33 at a reduced speed and carries the common p carrier 61 in that direction. Output 65 is thereby rotated in a direction opposite to the direction of input shaft 11.

OPERATION-FIGURE 2 In the structure shown in FIG. 2, the clutch 97, one-` Way clutch 91 and brake 47 are applied for manual low.

When turbine 5 is rotated, clockwise rotation of sleeve shaft 119 and sun gear 21 connected thereto will occur.v

Rotation of the sun gear 21 causes the planets 25 to rotate about their axes in a reverse direction. Planets 25 in turnV nected thereto then rotates at a reduced speed transferring the increased torque to the vehicle drive wheels which are" not shown. This torque multiplication is used to initially move the vehicle or when exceptional performance is` demanded, such as in situations Where mud, deep sand,

snow and long, steep hills are encountered. Since, in`

manual low, clutch 93 connects theinput sun gear 21 to the turbine 5, the torque converter can be effectively used to obtain engine braking when descending steep' hills and can also. be used for vehicle starting by pushing,

if necessary.

.In automatic low, one-way clutch 91 and brake 47 are still applied; clutch 97 is released and sun gear 31 is held for reaction by brake 47. When turbine 5 transmits torque i to the sleeve shaft 119 the sun gear 21 will be rotated clockwise. The long planets 25 will then be rotated in a counterclockwise direction and the short planets 29 meshing therewith will rotate clockwise and walk clockwise around the reaction sun gear at a reduced speed. The

carrier 61 for the planet gears then rotates at a speed less than that of the input sun gear 21 and the planetary gear train functions as a torque-increasing, speed-reducing unit.

In direct drive, the clutch 161 and normally one-way clutch 91 are engaged. The turbine 5 when rotated will rotate sleeve shaft 119 and the input sun gear 21 in a clockwise direction while direct mechanical drive will come from input shaftk 11 through shaft 1'51 and clutch 1`01 to rotate ring gear 21 clockwise. It will thus be seen that there will be split torque input with the engine torque applied to ring gear 27 and converter torque applied to sun gear 21, causing both gears to rotate forwardly. Since the ring gear 27 will be rotating slightly faster than the sun gear 2'1 the long planets will be carried by these rotating gears and will also rotate slowly in the forward direction walkingaround the rotating sun gear. The' planet carrier which is attached to and `carried b'y the planets rotates clockwise rotating the output shaft f substantially in a 1:1 input-to-output ratio.

In overdrive, when it i-s desired to have the output shaft 65 Vrotating faster than input shaft 11, clutch 101 and brake 47'r are applied. vThe ring gear 27 is connected through the clutch' 101 and shaft 151 directly to drive shaft 11'. With the sun gear 3Ih'eldl securely by brake 47`the short planets will rotate rapidly in a clockwise direction and race around the reaction sun gear. Planet 25 will turn slowly counterclockwise while orbiting clockwise around sun gear 21. The carrier for the planets is rotated in a clockwise direction and rotates faster than the input ring gear 27'. The output shaft 65 attached tothe carrier is rotated thereby faster than theY rotation of. input shaft 11.

T6 obtain reverse, thereverse ring gear 33 is held 'by brake band 491 Turbine 5,-th1jough one-wayy clutch 91 and clutch 93 which are engaged and shaft 119, rotates sung'ear`21cloc'kwise. Planets 25, rotated thereby in a reverse direction, rotate meshing. short planets 29 clockwise; The short planets 29 then walk. counterclockwise in the reaction. ring gear, producing'` a gearI reduction and moving carrier 61 in that.. direction. The output shaft 65 attached to the carrierV 61 is then rotated' in a reverse direction.

OPERATION-FIGURE 3 It is anticipated that the planetary gear unit of FIG. 2 withV its brakes and clutches can be employed with the torque converter of embodiment of FIG. 3*. If a solid overdrive' with the converter lockedi out, such" as in structure of FIGS;v l and 2r above,y is noti desired the overdrive ring gear' 27v may'y ybe driven by the turbine. As

illustrated in' FIG't 3', the drive shaft 251" is connected to the turbine 3 forV rotationl therewith'.

Wheniclut'cli 101 is. engaged" the turbine 5` will drive itle'ring, gear 27fclock'wis'e. If the sun gear 31 is held tfor `reaction by brake 4'7', the planets will orbit rapidly .'around'gvth'e reaction sun gear rotating carrier 61V faster than the input ring gear is rotating. Since the output shaft" 65 attached. to thel carrier" will; berotatingV faster :than the' input shaft'1`1, overdrive is obtained.

The u nderdrives and the reversedrive which can be lobtained with .the 'embodiment' ofv FIG. 3 are identical toi that of FIG; 2, and the description thereof is the :same as the descriptionv of these FIG. 2 drives. Direct 1driveis'similar toV that of FIG'. 2 with one-way brake 91' and'clutch 101' engaged. However, in FIG. 3 direct drive, all torque is through the converter.

From the above description ofv the preferred embodiments of tlii's invention, it will be understood that applicant has provided a power transmission which incorporates a torque converter and a single compound planetary gear set having independent ratio steps which provides# underdrives when torque multiplication is needed?, normal drives including converter drives and combined converter'and direct mechanical drives when 8. higher speeds are desired and greater torque multiplication is not needed, direct mechanical and torque converter overdrives, as well as reverse drives.

It will be understood that the invention can' be modified beyond the illustrated embodiments', and'therefo're any limitations to be imposed are those set forth in the followingl claims.

I claim: A

1. In a power transmission a power input means and output means, a hydrodynamic torque converter, said torque converter includinga pumpV operatively connected to said input means and a turbine and a stator, a planetary gear set having first and secondv sun gears, first planet gears meshing with said first sun gear, second planet gears meshing with said second' sun gear and said first planet gears, a ring gea'r meshingv with said first planet gears, a carrier rotatably supporting said" first and second planet gears, means connecting said carrier to said output means, a first drive shaft for transmittingtorque from said turbine to' said first sun gear, selectively engageable friction 4means tof' retardl rotation of said second sun gear to' condition said planetary gear set for underdrive when said first sun gear` is driven by said turbine, a second torque transmitting drive shaft connected to said input means for transmitting torque from said input means to said ring,V gear, selectively engageable friction means ,operatively connected to said second torque transmitting drive shaft engageable to connect said seconddrive sh'aftand said ring gear, said first selectively engageable friction means' being operative when applied to retard rotation of said second sun gear to condition said planetary gear set for overdrive when said last recited friction means is engaged and said input means drivesV said ring gear, and one-way friction meansV in said first dirivesh'aft to prevent said turbine from retarding rotation of said first sun gear and said output member when said planetary gearl set is'conditioned for overdrive.

2. The transmission defined' in claim 1 andfurther including a selectively engageable friction device-r operatively connected to said first' drive shaft in parallel` with said one-way friction means engageable vto enable said output means to `be utilized to drive said turbine.

3. In a power transmission, input means. and output means, a torque converter, said torque converter including a4 pump operatively connected to saidinputmeans and a turbine and a stator, a planetary gear set having.

first and second sun gears, first planet gears meshing with said first sun. gear, second planet gears meshing withy said second sun gear andV said first planet gears, a ring gear meshingwith said first planet gears,.a.carrier rotatably supporting said first and second planet) gears, means connecting said carrier to said output means, a first drive shaft connected to said turbinel for transmitting torque from said turbine' tol saidl first sun. gear,l

selectively engagea'ble' friction means to retard rotationv of said second sun gear to condition said planetary gear set for overdrive when said first` sun gear is driven byV said turbine, a second torque transmittingV drivei shaft connected to, said turbine for transmitting torquez from said turbine to said ring gear, selectively engageable friction means operatively connected4 to said second torque transmitting drive shaft engageableY toconnect said second drive shaft and said ringr gear, said firstselectively;

engageable'breaking/ means being operative when applied to retard rotation of said second sun gear t0 condition said planetary gear set for overdrive when said turbine drives said ring gear, one-way friction means in said first driveshaft engagea-ble to transmit torque fromV said turbine to said first sun gear for direct drive and automatically disengageable to prevent saidturbinefrom retarding rotation of said-first sun gear when said planetary gear set is conditionedfor overdrive and a selectively engageable friction means operatively connectedto said first drive shaft in parallel with said one-way friction turbine.

References Cited UNITED STATES PATENTS smirl 74-688 5 Waclawek 74-761 X Karcsson et a1. 74-688 Nash 74-688 X Forster 74-688 Wickman 74-688 10 Preston 74-688 Kronogard et a1. 74-688 Dodge 74-688 X 10 Hardy 74-763 X Winchell 74--761 Moore 74-159 X Fisher 74-761 X Jandesek 74-68-8 General et a1. 74--688 Simpson et al. 74-688 Stockton 74-688 DONLEY I. STOCKING, Primary Examiner.

DAVID I. WILLTAMOWSKY, Examiner.

J. R. BENEFIEL, T. C. PERRY, Assistant Examiners. 

1. IN A POWER TRANSMISSION A POWER INPUT MEANS AND OUTPUT MEANS, A HYDRODYNAMIC TORQUE CONVERTER, SAID TORQUE CONVERTER INCLUDING A PUMP OPERATIVELY CONNECTED TO SAID INPUT MEANS AND A TURBINE AND A STATOR, A PLANETARY GEAR SET HAVING FIRST AND SECOND SUN GEARS, FIRST PLANET GEARS MESHING WITH SAID FIRST SUN GEAR, SECOND PLANET GEARS MESHING WITH SAID SECOND SUN GEAR AND SAID FIRST PLANET GEARS, A RING GEAR MESHING WITH SAID FIRST PLANET GEARS, A CARRIER ROTATABLY SUPPORTING SAID FIRST AND SECOND PLANET GEARS, MEANS CONNECTING SAID CARRIER TO SAID OUTPUT MEANS, A FIRST DRIVE SHAFT FOR TRANSMITTING TORQUE FROM SAID TURBINE TO SAID FIRST SUN GEAR, SELECTIVELY ENGAGEABLE FRICTION MEANS TO RETARD ROTATION OF SAID SECOND SUN GEAR TO CONDITION SAID PLANETARY GEAR SET FOR UNDERDRIVE WHEN SAID FIRST SUN GEAR IS DRIVEN BY SAID TURBINE, A SECOND TORQUE TRANSMITTING DRIVE SHAFT CONNECTED TO SAID INPUT MEANS FOR TRANSMITTING TORQUE FROM SAID INPUT MEANS TO SAID RING GEAR, SELECTIVELY ENGAGEABLE FRICTION MEANS OPERATIVELY CONNECTED TO SAID SECOND TORQUE TRANSMITTING DRIVE SHAFT ENGAGABLE TO CONNECT SAID SECOND DRIVE SHAFT AND SAID RING GEAR, SAID FIRST SELECTIVELY ENGAGEABLE FRICTION MEANS BEING OPERATIVE WHEN APPLIED TO RETARD ROTATION OF SAID SECOND SUN GEAR TO CONDITION SAID PLANETARY GEAR SET FOR OVERDRIVE WHEN SAID LAST RECITED FRICTION MEANS IS ENGAGED AND SAID INPUT MEANS DRIVES SAID RING GEAR, AND ONE-WAY FRICTION MEANS IN SAID FIRST DRIVE SHAFT TO PREVENT SAID TURBINE FROM RETARDING ROTATION OF SAID FIRST SUN GEAR AND SAID OUTPUT MEMBER WHEN SAID PLANETARY GEAR SET IS CONDITIONED FOR OVERDRIVE. 